In a military sexual assault prosecution, the investigation usually focuses on one person early. Once that focus sets in, leads pointing to a different perpetrator can go unexamined. When the defense later argues that someone else committed the offense, the strength of that argument often depends on whether investigators pursued or ignored evidence of an alternate suspect. Whether a failure to investigate alternate suspects rises to a due process violation depends on a careful distinction between what the government suppressed and what it simply never collected.
The constitutional baseline
The Due Process Clause guarantees an accused a fair trial, and a central component of that guarantee is the prosecution’s duty to disclose favorable evidence. Under Brady v. Maryland, 373 U.S. 83 (1963), the government must turn over evidence favorable to the accused that is material to guilt or punishment, including evidence that points toward a different suspect. Courts have recognized that evidence of an alternate suspect can be powerful Brady material, because in the hands of the defense it can support an alternative theory of the crime and can be used to discredit the thoroughness of the investigation.
These principles apply in courts-martial. The military discovery rules, including Rule for Courts-Martial 701, reinforce the constitutional duty by requiring trial counsel to disclose evidence favorable to the defense. So if investigators developed information about another possible perpetrator and the government withheld it, that is a classic due process problem, and the materiality standard governs the remedy: relief is warranted where there is a reasonable probability that disclosure would have changed the result.
Suppression versus failure to develop
The harder question is what happens when the alternate-suspect evidence was never gathered at all. There is an important difference between suppressing favorable evidence that exists in the government’s files and failing to investigate a lead that might have produced such evidence. The Brady duty attaches to evidence the government possesses or controls. It does not, by its own terms, require the police or investigators to chase down every conceivable lead.
This means a bare failure to investigate alternate suspects is not automatically a Brady violation. The constitutional violation is most clearly established when the government had favorable information about another suspect and did not disclose it. When investigators simply declined to pursue a lead, the defense must usually frame the problem differently.
How the defense uses an inadequate investigation
Even where a failure to investigate does not amount to a stand-alone due process violation, it remains a potent trial tool. The defense is entitled to attack the adequacy and objectivity of the investigation in front of the fact-finder. By showing that investigators locked onto the accused and ignored evidence pointing elsewhere, the defense can argue that the government’s case rests on a premature and incomplete inquiry, which can create reasonable doubt.
This line of attack is closely connected to the accused’s right to present a complete defense. An accused may offer evidence that a third party committed the offense, subject to the rules of evidence and a sufficient connection between the third party and the crime. Where investigators failed to test a viable alternate-suspect theory, the absence of that testing can itself be presented as a weakness in the government’s proof.
When failure to investigate damages the evidence itself
Failure to investigate alternate suspects becomes a stronger due process argument when the inaction allows favorable evidence to be lost or destroyed. If a delay in pursuing a lead causes physical evidence to degrade, surveillance footage to be overwritten, or a witness’s memory to fade, the defense may argue that the government’s lack of diligence deprived the accused of evidence that could have been exculpatory. Claims of this kind are evaluated under standards that examine whether the lost evidence was apparently exculpatory and whether the government acted in bad faith, which is a demanding test but one that recognizes the harm of a deficient investigation.
Sexual assault cases present distinct dynamics
Sexual assault prosecutions raise particular concerns about investigative tunnel vision. These cases often turn on identity, consent, and credibility, and they frequently lack neutral eyewitnesses. When the government’s theory depends heavily on a single account, the failure to run down evidence of another possible perpetrator, to test physical evidence against alternate sources, or to examine inconsistencies that point elsewhere can be especially damaging to the fairness of the proceeding. The defense can use these gaps both to argue for disclosure of anything the government did learn and to challenge the reliability of the conclusion that the accused is the perpetrator.
What an accused should do
For a service member facing a sexual assault charge, the practical steps are clear. Counsel should aggressively seek discovery of everything the investigation generated, including any information about other suspects, because suppression of such material is a genuine due process violation. Counsel should also independently investigate, because the defense often must develop the alternate-suspect evidence that the government did not. And counsel should be prepared to use the investigation’s shortcomings at trial, both to seek the exclusion or remediation of any prejudice and to argue that an incomplete inquiry cannot support a conviction beyond a reasonable doubt.
Because the line between non-disclosure and non-investigation determines whether a due process claim or a trial-strategy argument is the right vehicle, these issues should be analyzed early by qualified defense counsel who can identify what the government had, what it failed to pursue, and how each gap can be used to protect the accused.
Disclaimer
This article is provided strictly for general educational and informational purposes. It is intended to explain how the Uniform Code of Military Justice (UCMJ), the Rules for Courts-Martial, the Military Rules of Evidence, and related military administrative processes work as a matter of public legal education. It does not constitute legal advice, a legal opinion, or a recommendation about any particular case, and it is not a substitute for advice from a qualified military defense attorney who can evaluate the specific facts and command, service, and jurisdictional circumstances involved.
Reading this article, or contacting any website on which it appears, does not create an attorney-client relationship between the reader and any law firm, attorney, or author. Every court-martial, nonjudicial punishment action, administrative separation, and security-clearance matter turns on its own facts, the charged articles, the convening authority, the service branch, and the evidence, and outcomes vary widely from one case to another.
Military law also changes over time. The Military Justice Act of 2016 (effective January 1, 2019) and subsequent National Defense Authorization Acts renumbered and rewrote many punitive articles, revised the Article 32 preliminary hearing, and altered sentencing, clemency, and appellate procedures. Statutes, regulations, executive orders, the Manual for Courts-Martial, and decisions of the service Courts of Criminal Appeals and the Court of Appeals for the Armed Forces may have been amended, superseded, or reinterpreted after this article was written, and article numbers or procedures cited here may have changed.
For these reasons, no reader should act or decline to act based on this content without first consulting a licensed attorney experienced in military justice about their own situation. The author and publisher make no warranty, express or implied, as to the accuracy, completeness, timeliness, or current applicability of the information provided, and disclaim any liability for any action taken or not taken in reliance on it. If you are facing investigation, charges, or an adverse administrative action, time limits may apply, and you should seek qualified counsel promptly.